We were missing the previous automatic `: ` addition; noticed in
a failing ostree test.
Fix this by just calling the new API as the non-prefix case does too.
These are equivalent to the non-null throw, except that the returned
value is a NULL pointer. They can be used in functions where one wants
to return a pointer. E.g.:
GKeyFile *foo(GError **error) {
return glnx_null_throw (error, "foobar");
}
The function call redirections are wrapped around a compound statement
expression[1] so that they represent a single top-level expression. This
allows us to avoid -Wunused-value warnings vs using a comma operator if
the return value isn't used.
I made the 'args...' absorb the fmt argument as well so that callers can
still use it without always having to specify at least one additional
variadic argument. I had to check to be sure that the expansion is all
done by the preprocessor, so we don't need to worry about stack
intricacies.
[1] https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html
Following up to the previous commit, also shorten our use of
`g_set_error (..., G_IO_ERROR_FAILED, ...)`. There's a lot of
this in libostree at least.
See also https://bugzilla.gnome.org/show_bug.cgi?id=774061
